Unadjusted international enplanements - U.S. Department of Transportation, Bureau of Transportation Statistics (BTS), U.S. Air CarrierTraffic Statistics, http://www.rita.dot.gov/bts/acts

Seasonally-adjusted international enplanements - U.S. Department of Transportation, Bureau of Transportation Statistics (BTS) calculation from BTS U.S. Air CarrierTraffic Statistics, http://www.rita.dot.gov/bts/acts

Notes:

Data from all U.S. air carrier international, scheduled passenger flights